Tools like the Vasa Swim Ergometer and Halo Swim System are great for more targeted training, but an athlete can also get in a great swim workout with a more simple approach.
At the Playtri Performance Center in Dallas, Texas (a USA Triathlon Performance Center), head coach and former Olympic swimmer Ahmed Zaher has spent countless hours with athletes, and the rest of the Playtri coaches, developing strength training that really work for improving athletes' swim times.
Work the following routine into your strength training if you are ready to ramp up your swim fitness.
Do this routine as part of your normal strength training. Try to give yourself as little time as possible between each exercise to apply the most effective stress to the muscle groups. Repeat 2 to 4 times.